getProtocol() Method Example

getProtocol() method is defined in ServletRequest interface from javax.servlet package and inherited by HttpServletRequest.

With getProtocol() method, the Servlet Programmer can know what protocol (like HTTP/1.0 or HTTP/1.1) is used by the client from HTML file to call the Servlet.

Let us see what Java API says about this method.

• java.lang.String getProtocol():
  Returns the name and version of the protocol the request uses in the form protocol/majorVersion.minorVersion, for example, HTTP/1.1. For HTTP servlets, the value returned is the same as the value of the CGI variable SERVER_PROTOCOL.

The method getProtocol() returns a string, the protocol used in ACTION attribute of of FORM tag used by the client to call the servlet.

Example on getProtocol(): Let us see the output by writing a program.

HTML Program: ClientData.html

  Enter Your Name 
  

Observe, the client uses GET value for attribute METHOD.

web.xml entry for ClientInformation servlet

  efgh
  ClientInformation



  efgh
  /jasmine

Servelet Program: ClientInformation.java

import javax.servlet.*; 
import javax.servlet.http.*;
import java.io.*; 

public class ClientInformation extends HttpServlet
{
  public void service(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException
  {
    res.setContentType("text/html");
    PrintWriter out = res.getWriter();

    String str = req.getProtocol();
    out.println("req.getProtocol() : " + str);

    out.close();
  }
}

Output screen of ClientData.html with text field filled up. Anyhow, the text field does not have any purpose here.

The output screen when submit button is clicked.